A typical curtain wall includes a mullion structure in which mullions are fixed to a structural body of building, for example, such as concrete floor slab, steel framed truss or the like, transoms are stretched between adjacent mullions respectively, and panel members are mounted to a space defined by the adjacent two mullions and the transoms stretched therebetween. Such panel members are most often panes of glass, and often double pane glass sections, but other paneled building materials such as aluminum, granite, slate, or concrete are also utilized. Typically, the panel members are supported within the space with the aid of support chairs and setting blocks.